66 Flora of central France. 



there will result a great variation in their vegetation. In- 

 deed the fertile plains of Beauce have little relation with the 

 sand deserts of Sologne, and the sterile heaths of VIndre 

 resemble little those lands of rolled sand which, on the 

 hills of Nierre produce such beautiful forests. In general 

 fresh water calcareous lands afford many species which are 

 common to them and the oolitic lands, while the gravelly 

 portions, on the contrary, exhibit the vegetation of siliceous 

 grounds. In attrition grounds ( atterissemens ) more or less 

 ancient, which are known by the name of alluvion, and which 

 form often considerable extents of fine sand, the vegetation is 

 equally interesting to the botanist, and circumscribed from 

 that of ancient formations. The Silene otites, Crucinella 

 angustifolia^ Vicia monantha, Astrocarpus sesamoides, de- 

 light in those localities. 



M. Boreau concludes from his observations that others are 

 really only two kinds of soil, which are distinct with respect 

 to vegetable productions : — the siliceous, under whatever 

 form it presents itself; and the calcareous, to whatever for- 

 mation it belongs. He afterwards pays particular attention 

 to three divisions of central France, which draw from the 

 nature of their soil a characteristic aspect, and limits which 

 are truly natural ; these are Morvan, Sologne, and Brenne. 

 We regret not being able to follow him in all the inquiries 

 relative to those countries so little known, and so worthy 

 the attention of the botanist. 



The geological constitution of the soil exercises a great in- 

 fluence on the temperature, and consequently on the develop- 

 ment of beings which inhabit it. This remark serves to ex- 

 plain the variation of climate, which we observe in the dif- 

 ferent points of the central region. M. Boreau gives a long 

 list of species, which one would think belonged only to warmer 

 climates, and although these species cannot all receive the 

 qualification of meridional, at least their enumeration may 

 afford an idea of the points of contrast which the Flora of 



